Apparently on some versions of Debian, Ubuntu, and possibly other distros pkg_resources is separated into a separate OS package from setuptools or distribute, and it is possible to have pkg_resources without setuptools.

When users with systems like this try to install a project that uses use_setuptools to bootstrap it can bomb out by using the system-installed pkg_resources rather than the one included in the just-bootstrapped setuptools. The already imported pkg_resources is using the wrong workingset and is unable to find the necessary entry_points for setuptools to work correctly.

This also affects distribute_setup.py--should I submit a separate PR to distribute?